When a crop such as corn silage is harvested in the fall, the entire plant is removed leaving the soil exposed through the winter. These exposed soils are more prone to run-off and erosion of sediment and nutrients into surface waters. As a means to alleviate these issues, many farmers have started to plant cover crops following harvest. Growing a cover crop can have many positive benefits to the soil and the surrounding environment. Cover crops produce aboveground biomass that can absorb the impact of rain drops and slow the flow of water from melting snow. The root system also aggregates soil particles to create a porous network that allows for improved water drainage. Cover crops can also scavenge excess soil nitrogen, keeping the nitrogen from potentially being lost through leaching, and can also reduce weed pressure in the spring. Many farmers have asked what is the best strategy to terminate cover crops in order to reap the benefits from this practice? Cover crop management can also be paired with reduced tillage practices to further reduce potential erosion. Reduced tillage practices such as no-till, zone-till, and strip tillage cause minimal disturbance to the soil. No-till planting means that the planter seeds directly into untilled soil. No-till planters are equipped with coulters that cut into the soil, creating a slit into which a seed is dropped. Heavy press wheels are then used to close the slit and assure good seed to soil contact. Zone tillage is characterized by a very small ‘zone’ of tillage (5-6”) around the area of seed placement. Zone-till implements are often attached to the front of a corn planter. Strip tillage is another type of reduced tillage that creates an 8-10 inch “strip” of tilled soil around the area of seed placement. These areas of tillage can enable the soil nearest the seed to warm and dry faster than no-tillage systems. It has been suggested that zone and strip tillage may be more advantageous for heavier soil types. Over time minimizing tillage can lead to improvements in soil drainage, nutrient cycling, and crop yields.
Vermont, University of Vermont
Darby, Heather; Monahan, Susan; Cummings, Erica; Harwood, Hannah; and Madden, Rosalie, "Cover Crop Termination & Reduced Tillage Study" (2012). Northwest Crops & Soils Program. 248.